thought this was obvious, but i have submitted dual schematic in post #2, one without the 2mm DC and one with.

And it can be anything else then 2mm DC. What ever you think is best if you want to use external charging, the plus with this is of course high charge rate and minimal wear and tear one the USB, i think i use my USB connection ones a week at the most.

But again no need for this, charging via normal USB works as it should, and using this option will help on wear and tear on the USB since the dual scud or japod will mean half as many charges needed, just look at my moderate and light usage, and again under heavy usage you should still get a hole day's usage.